The Collision Model Between A Single Particle And A Spherical Cap Bubble In A Water Medium


A mechanistic model is developed to account for the collision between asingle particle and a single bubble in a liquid medium. Based on the model, twopenetration criteria are established under which the particle is predicted topenetrate through the bubble if any of the two criteria is satisfied. It is shown thatthe particle penetration is only a necessary, but not sufficient, condition for bubbledisintegration in the case of single particle-single bubble collision. The penetratedbubble is shown to deform into a doughnut shape and the subsequent bubblebreakage is made through the necking mechanism of the doughnut-shape bubble.Bubble disintegration occurs only if the penetrating particle has a diameter greaterthan the height of the doughnut-shape bubble. The column is constructed ofPlexiglas with an internal diameter 10 cm and a height of 180 cm. Experimentsare also performed for single particle-single bubble collision in water, using threedifferent particles (2 mm, 3 mm glass beads and 3*3 mm PVC cylinder) withReynolds no. and Weber no. are (953, 1512 and 840) and (5.68, 9.45 and 5)respectively . Two markedly different collision phenomena are observed. A smalland/or light particle is unable to penetrate through the bubble and is ejected aftercollision. A medium particle can penetrate through the bubble but may not breakthe bubble. The two phenomena are all well predicted by the proposed model.